Cracked shingles

Any idea what would have caused these shingles to crack like this?

They are about 5 yrs old.
Fairly consistent over whole roof surface (north and south facing)
Pitch about 3:12
No attic venting apart from perforated soffit


If they are surely 5 years old it certainly is a manufacturers defect, they look like 25 years old shingles…:shock:

How well was the attic ventilated?

I agree with Dale BTW

Check this link for info.

I would not be so quick to call these manufacture defects. Defects yes but the actual cause may not be certain.

These look exactly like what I have seen of “weather exposed storage” prior to delivery or installation. Materials act differently in their packaging than when they are exposed/installed to the elements.

Pallets upon pallets are sunbaked and condensing in packaging, rain soaked, frozen… for days, weeks, months… are then delivered may linger onsite exposed longer and then installed

Looks OK from the ground until the contractors tail lights disappear but in a short amount of time they look like what’s depicted

If you have a local “real lumber yard”, Habitat for Humanity or surplus store go look at the yard stored shingles, I’m sure you’ll find some broken bundles to observe.

I’ll try and get over to the RR distribution yard and get some pix

is it just me or is the site down???
i haven’t been able to click through for about 2 months now

is it just me or is the site down???
i haven’t been able to click through for about 2 months now–

It’s just you Barry!!

From a Building science researcher:

*Myth Two is that attics need to have lots of ventilation. Again, venting requirements are not based on rigorous scientific research.
TenWolde explains that attic venting originally arose as a moisture-control strategy for cold climates. Other purported benefits, such as longevity of the shingles, arose later. It is widely believed that increased attic venting will prolong the life of roofing shingles by cooling them. But research shows that venting has very little, if any, effect on shingle temperature. The most important issue in shingle temperature appears to be the color of the shingles. Light-colored shingles reflect sunlight and don’t get as hot as dark shingles.
One possible real benefit of attic venting in climates with large snowfalls is to reduce snow melt on the roof to avoid the formation of ice dams. But according to TenWolde, a more effective——and energy-efficient——way to control snow melt in almost all climates in the United States would be to use air barriers and insulation to prevent heat from entering the attic.

Thanx Mario,

I’ve run diagnostics and my system says it’s not able to make the connection at their end. Are you running IE, Firefox or …


They appear to be baking from improper ventilation.

Barry, works fine for me, in IE and Firefox.

Works here to Barry.

Marcel :slight_smile:


Bring some actual “tested” rather than anectdotal information from the masses to the debate that attic ventilation has anything but a small effect on shingle life. Did you follow and monitor, over their life, the shingles shown in the last picture on the above part of your site…and have another roof with the same shingles, same orientation, same slope with ventilation next door…if not, it’s defintely not scientific but anectdotal.

And we all know about anectdotal stuff believed and heard on the street… Remember the 1980’s when just “gay” people got and spread aids??

I have referred the board to a picture of a research roof of shingles with the same shingles both vented and unvented with no visible difference to be seen. Why does no one comment on that? A picture may be worth a thousand posts. There is more research available on the web>

I post information that I actually deal with and inspect on a daily basis. I’ve seen so many roofing shingles fail at early ages due to improper ventilation. I know (from experience) how to read a shingles defect. It’s either wear & tear from reaching it’s normal life expectancy, a manufacturer’s defect, improper installation techniques, mechanical damages or improper ventilation.

Did you ever go into an un-vented attic in mid-July and feel how hot that cavity is?

And you wonder why shingles fold as they do in an un-vented situation.

Most if not all manufacturers websites have something to say about inadequate ventilation being one of the major cause of premature deterioration and failure. I am fully aware it may be in they best interest to state that but based on my own observations and those of a family member who was a professional roofer for many years, the heat build up in attics does shorten the life of the shingles. I bought a brand new home in late 80s so I know the shingles were new. After only a few years I noticed the shingles were already showing signs of deterioration. I also noticed the home really had very poor ventilation and temps could and did reach 150 deg. in mid and late summer (FL gulf coast). I decided to add additional soffit vents and gable vents. I added a fan to one of the gable vents set on an in-line thermostat. The drop in attic temp was significant, my power bill actually dropped about $30 a month the first year and the shingles went on to last until this April when my brother and I re-roofed the house. I could have gotten perhaps another year or two out of them but chose not to wait. I can stay in the attic now in summer almost indefinitely with little discomfort. Before the shingles and roof framing trusses would be so hot you literally could not put your hand on them. I have made a conscious effort to note when I see roofs deteriorating like that to check the ventilation and almost invariably the attic has poor to no ventilation.

I have run across this exact cracking pattern. The shingles were manufactured by Certainteed. Two of the house had leftover shingles in the garage with the paper still intact. Both Certainteed. I have seen it on several roofs that were from 6 - 4 years old. Every roof is the same color and pattern. Collingwood, Wasaga Beach, Barrie and Alliston Ontario area.
One person actually has Certainteed rep onsite to look at them. He said they would last the regular life of the shingle and offered no othere advice.
No other buyer even addressed it when I advise them they need to monitor them closely and replace them at any time it shows signs of leaking.
I tell the buyer I cannot even begin to estimate how long they may or may not last.

On almost all the houses had adequate to good ventilation. ** It was not the issue.**

All you can do is note it on you report and advise the client the life may not be the average life of the shingle. That is all you can do.


I see your in Ontario…if those shingles failed because of poor ventilation I’ll kiss everyones a$$ here that even mentioned the possiblity…:shock:

Between cloudy skies and 6 months of decent weather, there is NO way in hell those shingles failed simply because of poor ventilation.

For one thing they don’t look like 5 year old shingles to begin with, but if they are, they are defective.

I’ve seen them installed in Arizona with attic temps reaching 175 degrees 9 months out of the year without ANY ventilation and Never saw any shingle manufactured in the last five years fail because of poor ventilation…manufacturer defect yes…heat…NO.

I have measured the surface temperatures of shingles here, over 200 degrees many times of the year.

The OP needs to verify what I can not tell for sure from the photos if the other colored pieces are a laminated add on or an applique add on, such as the Certainteed Horizon shingles.

Although I am a proponent of proper balanced attic ventilation, I highly doubt in any extremes, that a shingle would contain full body cracking from improper ventilation alone in a stated 5 year period of time.

The applique method from the CT Horizon shingles had applied too much excessive asphalt flooding for the architectural style shingle appearance.

From my previous life as a hot tar roofer, and anyone who knows a hot tar roofer can verify this point, if you put too much asphalt on, it will crack very shortly in its life. When the asphalt cracks, anything that is connected to it cracks as well.

My best guess, without knowing the brand of shingle is a manufacturing defect.


I have to agree with Dale and Ed on this one, because I can relate to both the mopped on asphalt and pitch roofs and unventilated attics and the symptoms of the above posted pictures, if in fact are only five years old, are definitely defective. IMHO

Marcel :slight_smile: :slight_smile:

One thing we know for sure is that they are cracked and dried out, while poor ventilation may not be the cause of failure on these particular shingles, you can bet the added heat helped in their failure. of course heat has an aging effect on shingles, if it didn’t then the Sun would have no adverse effects on them. You could simply coat them with a UV inhibitor and they would last forever. They crack and curl because they dry out, they are petroleum based asphalt and they loose their oil by evaporation and we know heat speeds up evaporation. poor sealing during manufacture will cause premature failure also, not to mention color. Light reflects heat and dark absorbs it. So I would say everyone here may be right. The shingles may have been installed 4 years ago, but they may have been made 20 years ago and stored outside. Note it, defer it and move on. IMO

From an old post I made 6 or so months ago. If anyone has the below issue of EDU, please notify me …mine has disappeared!!

" I’m thinking that virtually no one on these boards have ever had a subscription to the newsletter Energy Design Update or if they had they did not believe what they read. In the July 2006 issue (I believe;can’t find my copy at the moment), a Building Science Corp reseacher measured roof temps of dark roofing materials in Jacksonville, FL during the month of August. Yes, he found that the unvented roofs had higher temps at their surface (the hottest part of the shingle since the sun hits there) but over the month the average temp rise on the unvented roof surface was something like .2 degrees F, not likely to cause shingle failure."

I’m to believe that this part of the US has very hot exterior temps yet the roofing material temps did not rise very much on dark shingles!!! what does that say about the deterioration rate of the material…if it rises to 131 deg from 130, it will fail premturely?? And what about up north in Maine, Vermont, etc, will the same shingle fail much more quickly if the temp rises from 110 to 111 …and how many days of the year will it get that hot as opposed to Florida and Georgia…the same shingle used down there should fail years ahead of those installed up north since the average operating temps should be at least 10- 20-30-40 degrees hotter!!!

So you see that when the operating temp for the same shingles (vented or unvented) in north and south locations is so different and the south shingles are getting real hot (150-200 deg), a new quandary appears: Why aren’t the southern shingles failing many years ahead of northern shingles due to the extra heat??? Doesn’t appear to be a venting problem since a vented southern shingle will get to 130-40+ deg regularly while an unvented north shingle will rarely or never get that hot but still fail due to no venting??? If Dale is seeing 200 deg shingles in Arizona, they must have to replace them every 2 or 3 years!!!

By the way, what is the high temperature that causes a roofing shingle to fail prematurely??